Reflex copying process



Patented June 17, 1941 REFLEX COPYING PROCESS Gottlieb von Poser. TheoScherer, and Oskar Siis, Wiesbaden-Biebrich, Germany, assignors, bymesne assignments, to Helge Svenson, Goteborg, Sweden No Drawing.Application April 1938, Serial No.

200,162. In Germany April 5, 1937 14 Claims. (or 95-5) This inventionrelates to an improved reflex copying process.

It is known to duplicate originals which are hardly transparent or whichhave been written or printed upon on both sides in such a manner that aso-called reflex copy thereof is first made and the latter thenreproduced in any suitable manner. For this purpose transparent papers,which are sensitized with the usual silver compounds, which aregenerally. employed in photography, are used' as reflex copyingmaterials. To reproduce the reflex copies thus obtained, papers renderedsensitive to light by means of diazo compounds are frequently used. Thisprocess has the disadvantage that the development and'fixation of thereflex copies is comparatively complicated, since a number of baths mustbe used. It is, moreover, a disadvantage that negative reflex copies areobtained, so that it is necessary before reproducing on diazo printingmaterial to reverse them or first to make a positive intermediate copyon photographic material.

It has already been proposed also to sensitize the reflex copyingmaterials with diazo compounds, if desired with the addition of azo com-I ponents, since, by using such materials, the aforesaid disadvantagesare avoided. With the use of the normal diazo compounds andazocomponents usual in diazotype processes, reflex copies are generallyobtained which, however, can only be very badly reproduced on paperssensitized with diazo compounds and thus, on the whole, result in quiteuseless copies with wholly insufficient contrasts. That is one of thereasons that such a process could not hitherto be introduced inpractice. v

It has now been found that, contrary to former experience, reflexcopies, whichcan be successfully reproduced on the usualdiazo-photo-printing papers, can be made by using diazo compounds andazo components, if. the diazo compounds and azo components are chosen ina definite manner.

According to this invention those diazo compounds and azo components areused whichJon developing, give dyes which absorb light chiefly in theregion between about 3300A. to 4400 A. Such azo dyes are in generalyellow to greenishyellow. The excellent suitability of such reflexcopies for reproduction on diazo photo printing material depends uponthe fact that theprint dyestuffs absorb light in the same range of thespectrum as the diazo compounds generally used in photo printingprocesses.

This mode of procedure is contrary to the rules tinguishable. The reflexcopies obtained by the new'process however are quite indistinct, and,owing to the light tones of the lines, barely legible. In spite of this,they are eminently suitable for reproduction.

As a support for the light sensitive compound,

in accordance with the invention, cellulose hy drate sheets or foils arepreferably used. Advantageously, the cellulose hydrate sheet issensitized with the diazo compound and the azo component, so that thematerial may be developed according to the dry method. It is, however,also possible to spread on the diazo compound alone and then to developthe material by the wet method. Instead of a single diazo compound or asingle azo component, mixtures of several diazo compounds or mixturesof. several azo components can also be used. Hereby it can beadvantageous to add small "quantities of'a diazo compound or an azocomponent yielding darker tones to the mixture of dyestuii' component.Thus are obtained reflex copies with darker tones which are betterlegible. Besides these substances, the sheet or foil can also containbleaching dyes, such as, for example,

pinacyanol, with or without sensitizers, such as,/

for example, thiosinamine.

The reflex-copying process can be still further improved if, during thereflex copying, a further sheet, rendered light sensitive by means ofbleaching dyes or diazo compounds, is interposed between the source oflight and the reflex copying material, preferably'in contact with thelatter.

This sheet can, for example, be prepared with the same diazo compound asthe reflex copying material. An improvement in the reflex copies canfurthermore be obtained, namely by using, during the reflex copying,filters which contain stable substances absorbing ultra-violet light.Such substances are, for example, esculine, esculetine,fi-methylumbelliferone-carbonic acid andpyrenedisulphonic acid or thecorresponding alkali-salts. The process may, moreover, be so carried outthat the ultra-violet light-absorbing substances, which are preferablycolorless or only very slightly colored, are spread on one side of asheet, while the light sensitive preparation is spread on the otherside.

Surprisingly, it is even possible to incorporate these ultraviolet lightabsorbing substances directly in the light sensitive layer.

In carrying out the process, alkylphenols, for example, with one or morealkyl-groups, especially methylor ethyl-groups, in which the alkyl groupor one of the alkyl groups carries a substituent known to increase thesolubility in water, are suitable as azo components. Such substituentsare, for example, basic groups such as amino groups. These may be monoordisubstituted. As examples, the dimethylaminoor the phenylamino-groupmay be mentioned. Other suitable substituents are the carboxylgroup andthe hydroxyl-group. The sulphogroup may also be used, although the othersubstituents named are in general more advantageous. Compounds of thetype in question may, for example, be derived from cresols, such as theortho-cresol or the meta-cresol. Xylenols, such as1.4-dimethyl-2-phenol, or trimethylphenols, for example1.3.4-trimethyl2-phenol are also suitable. A few of the azo componentswhich can be used are, for example, 1-hydroxymethyl-2- phenol, thep-(2-hydroxyphenyl)-propionic acid CHr-CHr-COOH 2- (w-phenylamino)-metl'iyll-hydroxybenzene and 2- (w-dimethylamino) {methyl 1 hydroxy.benzene T",

CH: CHrN The latter compound is prepared by treatingo-nitrobenzylchloride with dimethylamine, reducing, diazotizing andboiling-out. In the same way the corresponding substitution products ofmetacresol can be used. Also suitable for use are, for example, thefollowing compounds: l-oxymethyl- 2-hydroxy-4methyl-benzene,l-(w-phenylamino) methyl-2-hydroxy-4-methylbenzene,p-(i-methyl-2-hydroxyphenyl) -glutaric acid CHr-COOH 1.4-dimethyl-2hydroxy- 3 hydroxymethylben zene, l-hydroxymethyl-z-hydroxy 3methoxybenzene, and l-(w-phenylamino)-methyl-2-hydroxy-B-methoxybenzene.The compounds mentioned can also, if desired, contain still furthersubstituents provided that the latter do not appreciably alter theabsorption of the dyestufis. Additional unsubstituted hydroxyl-groupsare not suitable as substituents for the above reasons.

. Substituents which appreciably decrease the solubility or the couplingpower are also unsuitable.

The said azo components give suitably good coating dyes with the proventertiary or particular secondary para-amino-diazo compounds, forexample, those which do not have in the amino group too long alkylgroups but only methylor ethyl-groups. Particularly advantageous arethose para-amino-diazo compounds which have a methyl group injuxtaposition to the amino group. For example4-monoethylamino-3-methyl-l-benzenediazoniumchloride is very suitable.Good results are also obtained with4-dimethylaminobenzene-l-diazoniumchloride or the4-diethylaminobenzene-ldiazoniumchloride. When carrying out the presentinvention it is advantageous to choose the dyestuff components in such amanner that, on developing, the dyestuff is formed as complete and asquick as possible. Thus, when using azo components which couple onlywith comparative difficulty, one should use diazo compounds with greatcoupling activity as, for example, para-aminodiazo compounds which haveas substituents a dichlorbenzyl residue in the amino group.

The following examples illustrate the invention:

1. Cellulose hydrate sheets are soaked in a solution of 12 grams of thediazonium chloride of 1-amin0-2-hydr0xy-4-ch1orbenzene-6 sulphonic acid,15 grams phloroglucine, 10 grams thiourea and 10 grams tartaric acid in1000 ccm. water and dried. During the preparation of a reflex copy withthis material, for which an arc lamp with a dull glass globe may, forexample, be used as the source of light, a cellulose hydrate-sheet,which is prepared by dipping it for 1-2 minutes in a .3% aqueoussolution of 4-methyl-umbelliferone-carbonic acid (in the form of thesodium salt) is laid on the side of the reflex copying material facingthe source of light. The said diazo compound is prepared by diazotizing2.4-dichlorl-aniline-fi-sulphonic acid and treating the diazo compoundwith soda solution, one chlorine atom being replaced by the hydroxylgroup.

2. Sheets of regenerated cellulose are placed for 1-2 minutes in a bathcontaining a solution of 15 grams of the zinc chloride double salt of4-dimethyl-aminobenzene -,1- diazoniumchloride, 10 grams phenol, 12grams tartaric acid and, if desired, softening and wetting agents in1006 ccm. of-water, and are then squeezed-out. The dried sheet is laidupon the original to be copied and exposed through the sheet for about 1minutes in sunlight. After the exposure the sheet is developed by meansof ammonia gas; a greenish-yellow print results which can be reproducedin the normal way on diazo photo printing papers.

3. The procedure of example 2 is followed, but for the sensitizing ofthe sheet a solution is used containing in 1000 ccm. water 15 grams ofthe zinc chloride double salt of 4-monoethylamino-3-methylbenzene-1-diazoniumchloride, 12 grams of2.5-dimethyl-6-w-dimethylaminomethyl-l-phenol CH2.N

12 grams citric acid and 2 grams esculine. The 2.5 dimethyl 6 w dimethylaminomethyl-lthe following pages.

phenol is obtained by condensation of 2.5-dimethyl-l-phenol withformaldehyde and dimethylamine after the known method described inAnnalen der Chemie, vol. 343, page 280 and 4. 14 grams of the zincchloride double salt of 4-diethylamino-benzene-l-diazoniumchloride aredissolved in 1000 com. water together with 12 grams phenol, gramstartaric acid and 2 grams methylesculetine. A sheet prepared with thissolution is suitable for the preparation of reflex copies whichreproduce well.

5. 70 grams of the zinc chloride double salt I of4-dimethylamino-2emethyl-benzene-1-diazoniumchloride are dissolved in1000 com. water together with 55 grams of 2.5-dimethyl-6-w-dimethylamino-inethyl-l-phenol and grams tartaric acid. This solution isspread on one side of a superficially saponified sheet of acetylcellulose. When making a reflex copy with the aid of this sheet theprepared side of the sheet is brought into contact with the original. Ondeveloping in ammonia, a greenish yellow dye is formed. If aparticularly high standard is required for the print to be madetherefrom, the

reflex copy can first once again be copied in the normal way on thematerial used for the reflex copying and the final copy.prepared fromthis intermediate copy. 1

6. A cellulose hydrate sheet is rendered sensitive to light by placingin a bath containing a solution of 15 grams of 4-(26-dichl0rbenzyl)-amino-l-benzenediazoniumsulphate, 11 grams of 2- (w-phenylamino)-methyl-l-hydroxybenzene, 10 grams thiourea and 10 grams tartaric acidin 1000 com. water. A reflex copy. is then prepared in the usual mannerby developing with ammonia gas. The reflex copy can be reproduced wellon normal diazo photo printing paper as the resultant greenish-yellowdye has an excellent coating capacity. Similar efi'ects can also beobtained if, instead of 2-(w-phenylamino)- methyl-l-hydroxybenzene, thefollowing components are used: p-(Z-hydroxyphenyhpropionic acid,2-(w-dimethylamino)-methyl-1- hydroxybenzene, 5- (3-hydroxyphenyl)-propionic acid, 3-(w-dimethylamino)-methyl-1-hydroxybenzene,3-(w-phenylamino) -methyl-1-hydroxybenzene,1-hydroxymethyl-2-hydroxy-3-methoxybenzene and .l-(w-phenylamino)-methyl-2- hydroxy-3-methoxybenzene. The 2- w-dimethylamino)-methyl-1-hydroxybenzene is prepared initially fromo-nitro-benzylchloride, by substitution of a dimethyl-amino residue forthe chlorine, reduction of the nitro group to the amino group,diazotizing and by boiling-out. The preparation of3-(w-dimethylamino)-methyl-1- hydroxybenzene is similar.

7. The procedure according to Example 6 is followed, but for sensitizingthe sheet a solution of 15 grams of the zinc chloride double salt of4-monoethylamino-3-methylbenzene-1-diazoniumchloride, 12 grams ofl-(w-phenylaminmmethyl-2-hydroxy-4-methylbenzene, 10 grams thiourea and10 grams citric acid in 1000 ccm. water is used. With similar results,instead of 1-(w-phenylamino)-methyl 2 hydroxy 4 methylbenzene,1-hydroxymethyl-2-hydroxy-4- methylbenzene, 1,4-dimethyl 2hydroxy-S-hydroxymethylbenzene and c-(4-methyl-2-hydroxyphenyD-glutaricacid may be used. The latter is prepared by condensation of m-cresol andacetone-dicarbonic acid to the corresponding cumarine-acetic acid,alkaline cracking of this product and catalytic hydrogenation.

We claim:

1. In a process for producing a reflex copy, the steps which compriseplacing a lightsensitive material sensitized by means of a diazocompound and an azo component which, on development, yield a. yellow togreenish-yellow dye, the chief absorption of which extends over theregion of'about 3300 A. to about 4400 A. upon the original which is tobe copied, causing light to fall upon the original through the saidlight-sensitive material developing the image thereon and reproducingthe developed image on a diazo-photo printing material by direct contactmethods.

2. In a process for producing a reflex copy, the steps which compriseplacing a light-sensitive transparent material sensitized by means of adiazo compound and an azo component which, on development, yield ayellow to greenish-yellow dye, the chief absorption of which extendsover the region of about 3300 A. to about 4400 A. upon the originalwhich is to be copied, causing light to fall upon the original throughthe said light-sensitive transparent material developing the imagethereon and reproducing the developed image on a diazo-photo printingmaterial by direct contact methods.

3. In a process for producing a reflex copy, the steps which compriseplacing a light-sensitive transparent material sensitized by means of apara-amino diazo compound and an alkyl phenol which contains only onephenolic hydroxyl group upon the original which is to be copied, causinglight to fall upon the original through the said light-sensitivetransparent material developing the image thereon and reproducing thedeveloped image on a diazophoto printing material by direct contactmethods.

4. In a process for producing a reflex copy, the steps which compriseplacing a light-sensitive transparent material sensitized by means of apara-amino-diazo compound and an alkyl phenol which contains only onephenolic hydroxyl group and carries in the alkyl group a substituentselected from the group consisting of the hydroxyl-, carboxyl-, sulfoand amino groups upon the original which is tobe copied, causing lightto fall upon the original through the said lightsensitive transparentmaterial developing the image thereon" and reproducing the developedimage on a diazo-photo printing material by direct contact methods.

5. In a process for producing ajreflex copy,

the steps which comprise placing a light-sensitive transparent materialsensitized by means of a para-amino diazo compound and a 1.4-dimethyl-2-hydroxybenzene compound which contains only one phenolic hydroxylgroup and a methyl group carrying a substituent selected from the groupconsisting of the hydroxyl-, carboxyl-, sulfoand amino groups upon theoriginal which is to be copied, causing light to fall upon the originalthrough the said light-sensitive transparent material developing theimage thereon and reproducing the developed image on a diazophotoprinting material by direct contact methods.

6. In a process for producing a. reflex copy, the steps which compriseplacing a light-sensitive transparent material sensitized by means of asecondary para-amino diazo compound and an alkyl phenol which containsonly one phenolic hydroxyl group and carries in the alkyl group asubstituent selected from the group consisting of the hydroxyl-,carboxyle, sulfoand amino groups upon the original which is to becopied, causing light to fall upon the original through the saidlight-sensitive transparent material developing the image thereon andreproducing the developed image on a diazo-photo printing material bydirect contact methods.

7. In a process for producing a reflex copy, the steps which compriseplacing a light-sensitive transparent material sensitized by means of4-mono-ethyl-amino-3-methyl-1-benzene-diazomum-chloride and an alkylphenol which contains only one phenolic hydroxyl group upon the originalwhich is to be copied, causing light to fall upon the original throughthe said lightsensitive transparent material developing the imagethereon and reproducing the developed image on a diazo-photo printingmaterial by direct contact methods.

8. In a process for producing a reflex coplh.

the steps which comprise placing a lightsensitive transparent materialsensitized by means of4-mono-ethyl-amino-3-methyl-1-benzene-diazonium-chloride and an alkyl'phenol which contains only one phenolic hydroxyl group and carries inthe alkyl group a substituent selected from the group consisting of thehydroxyl-, carboxyl-, sulfoand amino groups upon the said original,causing light to fall upon the original through the said light-sensitivetransparent material developing the image thereon and reproducing thedeveloped image on a diazophoto printing material by direct contactmethods.

9. In a process for producing a reflex copy, the steps which compriseplacing a lights'en'sltive transparent material sensitized by means of4-mono-ethyl-amino-3-methyl-l-benzene-diazonium-chloride and a1.4-dimethyl-2- hydroxybenzene compound which contains only one phenolichydroxyl group and a methyl group carrying a substituent selected fromthe group consisting of the hydroxyl-, carboxyl-, sulfoand amino groupsupon the original which is to be copied, causing light to fall upon theoriginal through the said light-sensitive transparent materialdeveloping the image thereon and reprodue-ing the developed image on adiazo-photo printing material by direct contact methods.

10. In a process for producing a reflex copy, the steps which compriseplacing a lightsensitive transparent material zene-diamonium-chlorideand 2.5-dimethyl-6-wdimethyl-amino-methyl-l-phenol upon the originalwhich is to be copied, causing light to fall upon the original throughthe said light-sensitive transparent material developing the imagethereon and reproducing the developed image on a diazo-photo printingmaterial by direct contact methods.

sensitized by means of 4-mono-ethyl-amino-3-methyl-1-bene diazo compoundand an azo component which, on development, yield a yellow togreenish-yellow dye, the chief absorption of which extends over theregion of about 3300 A. to about 4400 A. upon the original which is tobe copied, causing light to fall upon the original through the saidlight-sensitive transparent material and a light filtering materialdeveloping the image on the light-sensitive transparent material andreproducing the developed image on a diazo photo printing material bydirect methods.

12. In a process for producing a reflex copy, the

steps which comprise placing a light-sensitive transparent materialsensitized by means of a diazo compound and an azo component which, ondevelopment, yield a yellow to greenish-yellow dye, the chief absorptionof which extends over the region of about 3300 A. to about 4400 A. uponthe original which is to be copied, causing light to fall upon theoriginal through the said light-sensitive transparent material, whileinterposing between the source of light and said transparent material asheet treated with an ultra-violet light-absorbing substance, developingthe image on the light-sensitive transparent material and reproducingthe developed image on a diazo photo printing material by directmethods.

13. In a process for producing a reflex copy, the steps which compriseplacing a; light-sensitive transparent material sensitized on one sideby means of a diazo compound and an azo com- 11. In a process forproducing a reflex copy, the

steps which comprise placing a light-sensitive transparent materialsensitized by means of a ponent which, on development, yield a yellow togreenish-yellow dye, the chief absorption of which extends over theregion of about 3300 A. to about 4400 A. and treated on'the other sidewith an ultra-violet light-absorbing substance upon the original whichis to be copied the diazo sensitized side contacting the said original,causing light to fall upon the original through the said light-sensitivetransparent material, developing the image on the light-sensitivetransparent material and reproducing the developed image on a diazophoto printing material by direct methods.

14. In a process for producing a reflex copy, the steps which compriseplacing a light-sensitive transparent material sensitized by means of adiazo compound and. an azo component which,

on development, yield a yellow to greenish-yellow dye, the chiefabsorption of which extends" over the region of about 3300 A. to about4400 A. and having incorporated in the sensitive layer an ultra-violetlight-absorbing substance upon the original which isto be copied,causing light to Za se sitive transparent material, developing the imageon the light-sensitive transparent material and reproducing thedeveloped image on a diazo photo, printing material by direct methods.

/ Go'r'rmEB VON POSER.

THEO SCHERER. OSKAR siis.

11 upon the original through the said light--

